Method of processing a substrate

ABSTRACT

In a method of processing a substrate in accordance with an embodiment, a trench may be formed in the substrate, imprint material may be deposited at least into the trench, the imprint material in the trench may be embossed using a stamp device, and the stamp device may be removed from the trench.

TECHNICAL FIELD

Embodiments generally relate to a method of processing a substrate.

BACKGROUND

In semiconductor processing it may be desirable to realizethree-dimensional (3D) structures. Approaches to realize 3D structuresinclude, for example, lithographic processes. However, creating 3Dstructures by means of lithographic processes may be toilsome (forexample, a high number of process steps may be required) and/or costly(for example, due to use of two-photon absorption processes, expensivetools). Standard processes (e.g. standard microlithography processes ornanoimprint processes) may define only two-dimensional (lateral)structures.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, emphasis instead generally being placed upon illustrating theprinciples of embodiments. In the following description, variousembodiments are described with reference to the following drawings, inwhich:

FIG. 1 is a diagram illustrating a method of processing a substrate inaccordance with an embodiment;

FIG. 2 is a diagram illustrating a method of processing a substrate inaccordance with an embodiment;

FIG. 3 shows a schematic perspective view of an exemplarythree-dimensional structure that may be obtained by means of a method ofprocessing a substrate in accordance with an embodiment;

FIG. 4 shows a schematic perspective view of a stamp device configuredas a stamp that may be used in a method of processing a substrate toobtain the three-dimensional structure of FIG. 3 in accordance with anembodiment;

FIGS. 5A to 5G show schematic cross-sectional views of a substrate forillustrating different stages in a method of processing a substrate inaccordance with an embodiment;

FIG. 6 shows a schematic cross-sectional view of a substrate forillustrating formation of metallization structures using a method ofprocessing a substrate in accordance with an embodiment;

FIG. 7 shows a schematic top view of a die array for illustratingformation of die metallization structures using a method of processing asubstrate in accordance with an embodiment;

FIG. 8 shows a schematic perspective view of a die for illustratingformation of die metallization structures using a method of processing asubstrate in accordance with an embodiment;

FIGS. 9A to 9E show schematic cross-sectional views of a substrate forillustrating different stages in a method of processing a substrate inaccordance with an embodiment;

FIG. 10 shows a schematic cross-sectional view of a stamp deviceconfigured as a roll that may be used in a method of processing asubstrate in accordance with some embodiments.

DESCRIPTION

The following detailed description refers to the accompanying drawingsthat show, by way of illustration, specific details and embodiments inwhich the invention may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice theinvention. Other embodiments may be utilized and structural, logical,and electrical changes may be made without departing from the scope ofthe invention. The various embodiments are not necessarily mutuallyexclusive, as some embodiments can be combined with one or more otherembodiments to form new embodiments.

The term “layer” or “layer structure” as used herein may be understoodto refer to a single layer, or to a layer sequence (also referred to aslayer stack) including a plurality of sublayers. In a layer sequence orlayer stack the individual sublayers may, for example, include or may bemade of different materials, or at least one of the sublayers mayinclude or may be made of the same material as another one of thesublayers.

The terms “disposed on”, “arranged on” or “formed on” as used herein maybe understood to refer to a layer (or some other element or entity) thatmay be located in direct mechanical and/or electrical contact on anotherlayer (element or entity). A layer (element or entity) may also belocated in indirect (mechanical and/or electrical) contact with anotherlayer (element or entity), in this case one or more additional layers(elements or entities) may be present in-between.

The terms “disposed over”, “arranged over” or “formed over” as usedherein may be understood to refer to a layer (or some other element orentity) that may be located at least indirectly on another layer(element or entity). That is, one or more other layers (elements orentities) may be located between the given layers (elements orentities).

The terms “electrically connected”, “electrically contacted” or“electrically coupled” may be understood to include both a directelectrical connection, contact or coupling and an indirect electricalconnection, contact or coupling.

FIG. 1 is a diagram illustrating a method 100 of processing a substratein accordance with an embodiment.

In accordance with an embodiment, the substrate may be a semiconductorsubstrate, in other words a substrate that may include or may be made ofone or more semiconducting materials. For example, the substrate mayinclude or may be made of silicon (Si), alternatively any other suitablesemiconductor material such as e.g. germanium (Ge), a IV-IV compoundsemiconductor (e.g. SiGe), a III-V compound semiconductor (e.g. GaAs), aII-VI compound semiconductor (e.g. CdTe), or any other suitablesemiconductor material.

In accordance with an embodiment, the substrate may be or may include awafer, or may be part of a wafer, for example a semiconductor wafer suchas for example a silicon wafer, alternatively any other suitablesemiconductor wafer.

In accordance with another embodiment, the substrate may be or mayinclude a printed circuit board (PCB).

In 102, a trench may be formed in the substrate.

In accordance with an embodiment, forming the trench may include an etchprocess. In other words, the trench may be formed using an etch process,for example a standard trench etch process. In accordance with anotherembodiment, forming the trench may include a cutting process. In otherwords, the trench may be formed using a cutting process. In accordancewith other embodiments, forming the trench may be achieved by means ofother suitable processes.

In accordance with an embodiment, a barrier layer may be deposited. Thebarrier layer may be deposited before depositing imprint material intothe trench (see below). In accordance with an embodiment, the barrierlayer may be deposited over a sidewall or sidewalls of the trench. Thebarrier layer may be deposited using any suitable layer depositionmethod.

In accordance with an embodiment, a seed layer may be deposited. Theseed layer may be deposited before depositing imprint material into thetrench (see below). In accordance with an embodiment, the seed layer maybe deposited over a sidewall or sidewalls of the trench. In accordancewith an embodiment, the seed layer may be deposited over at least a partof the barrier layer (if provided). The seed layer may be depositedusing any suitable layer deposition method.

In 104, imprint material may be deposited at least into the trench.

The term “imprint material” as used herein may be understood to includematerials that may be patterned or structured by means of embossing orimprinting, for example materials that may be patterned or structuredusing a stamp device (such as, for example, a stamp or imprint stamp, ora roll) having an imprint structure or pattern (e.g. a micro-imprintstructure or nano-imprint structure).

In accordance with an embodiment, the imprint material may be depositedsuch that the trench is partially filled with the imprint material. Inaccordance with another embodiment, the imprint material may bedeposited such that the trench is completely filled with the imprintmaterial.

In accordance with an embodiment, the imprint material may include ormay be a hardenable material.

The term “hardenable material” as used herein may be understood toinclude materials that may change or may be transformed from a firststate of lower hardness or resistivity (also referred to as non-hardenedstate) to a second state of, compared to the first state, higherhardness or resistivity (also referred to as hardened state). Thechangeover from the first (non-hardened) state to the second (hardened)state may also be referred to as “hardening” or “toughening”.

In accordance with some embodiments, in case that the imprint materialincludes or is a hardenable material, the imprint material may bedeposited while it is in the non-hardened state.

In accordance with an embodiment, the hardenable material may include ormay be a polymeric or polymerizable material, for example a polymericresist material in accordance with an embodiment, e.g. a photosensitiveresist material (or photo resist) in accordance with an embodiment, e.g.an UV (ultraviolet) sensitive photo resist in accordance with anembodiment, or a thermosensitive resist material in accordance withanother embodiment.

In case that a polymeric or polymerizable material (for examplepolymeric resist material, e.g. photo resist) is used as hardenablematerial, hardening may illustratively be accomplished by cross-linkingof polymer chains of the polymeric or polymerizable material (forexample polymeric resist material, e.g. photo resist). In thisconnection, hardening the polymeric or polymerizable material may alsobe referred to as curing and the hardenable material may also bereferred to as curable material.

In accordance with some embodiments, the hardenable material may beconfigured such that cross-linking of the polymer chains may be achievedby means of light illumination or irradiation (in case of aphotosensitive resist material), for example by means of UV irradiation(e.g. in case of an UV sensitive resist material), in other words byexposing the material to light (e.g. UV light), and may, for example,lead to a change in the solubility of the polymeric or polymerizablematerial (for example polymeric resist material, e.g. photo resist).

In accordance with another embodiment, the hardenable material may beconfigured such that cross-linking of the polymer chains may be achievedby means of applying elevated temperatures (e.g. tempering or annealprocess). For example, hardenable materials that may be hardened bymeans of elevated temperatures may include thermosetting materials.

In accordance with still another embodiment, the hardenable material maybe configured such that hardening or curing (e.g. cross-linking) of thehardenable material may be achieved by applying an electrical voltage tothe hardenable material.

In accordance with still another embodiment, the hardenable material maybe configured as a self-hardening material, in other words as a materialthat may harden without external influence (e.g. without applyingirradiation, elevated temperatures or electrical voltages), for examplejust after expiry of a certain amount of time.

In accordance with another embodiment, the imprint material may includeor may be a mold compound.

In accordance with another embodiment, the imprint material may includeor may be a nanopaste material.

The imprint material may be deposited using any suitable depositionmethod. For example, in accordance with some embodiments, in case thatthe imprint material includes or is an imprint resist, the imprintmaterial may be deposited using any suitable resist deposition methodsuch as, for example, a spin-coating method in accordance with anembodiment. In accordance with other embodiments, other suitabledeposition methods may be used.

In accordance with some embodiments, depositing the imprint material mayfurther include depositing the imprint material over at least a part ofthe substrate surface, for example at least over a part or parts of thesubstrate surface that are proximate or adjacent the trench inaccordance with an embodiment. The imprint material may, for example,cover the substrate surface.

In accordance with one embodiment, depositing the imprint material mayinclude coating the substrate (e.g. wafer) with a layer (e.g. thicklayer) of imprint material (e.g. imprint resist).

In 106, the imprint material may be embossed using a stamp device.

The term “stamp device” as used herein may be understood to includedevices, for example stamps, that may be used for embossing orimprinting an imprint material, thereby patterning or structuring theimprint material. In accordance with some embodiments, the stamp devicemay, for example, include or may be a stamp. In this case the stamp mayalso be referred to as imprint stamp. In accordance with otherembodiments, the stamp device may, for example, include or may be astructured roll.

In case that the imprint material includes or is a hardenable material,the imprint material may be embossed while it is still in thenon-hardened state.

In accordance with some embodiments, the stamp device (e.g. stamp) mayinclude at least one imprint pattern or structure that may be suitablefor embossing structures in the trench. For example, in accordance withan embodiment, the stamp device (e.g. stamp) may include one or moremicro-imprint structures. The term “micro-imprint structure” as usedherein may be understood to include imprint structures or patterns, oneor more spatial dimensions (i.e. length, width, height) of which are inthe micrometer range (for example, on the order of magnitude of a fewmicrometers, of a few tens of a micrometer, or of a few hundreds of amicrometer). In other words, a “micro-imprint structure” may refer to animprint structure having a length and/or width and/or height in themicrometer range.

In accordance with some embodiments, the stamp device (e.g. stamp) mayinclude an imprint pattern (also referred to as imprint structure) thatmay correspond to an inverse (or negative) of a mask structure or maskpattern (also referred to as three-dimensional (3D) mask structure orpattern) to be formed at least in the trench. In accordance with someembodiments, the imprint pattern may correspond to an inverse (ornegative) of a 3D mask structure to be formed in the trench and over atleast a part of the substrate surface. The 3D mask structure maycorrespond to the patterned imprint material that may be obtained byembossing the stamp device (e.g. stamp) (having the imprint pattern)onto the imprint material.

In accordance with some embodiments, the stamp device (e.g. stamp) maybe configured such that the imprint pattern may reach at least partiallyinto the trench when embossing the imprint material. In accordance withan embodiment, the trench and/or stamp device (e.g. stamp) may beconfigured such that a lower end of the stamp device (e.g. stamp)(illustratively, that end of the stamp device (e.g. stamp) that facesthe bottom of the trench) may be spaced apart from the bottom of thetrench when embossing the imprint material. In other words, inaccordance with an embodiment, the depth of the trench may be such thatthe lower end of the stamp device (e.g. stamp) (or of the stamp device'simprint pattern) will not reach or contact the bottom of the trench whenembossing the imprint material. Thus, a layer of imprint material may,for example, remain between the trench bottom and the lower end of thestamp device (e.g. stamp) when the stamp device (e.g. stamp) is placedin the trench. Therefore, a mask structure that may be formed by theembossed imprint material may cover the entire bottom of the trench inthis case. In accordance with other embodiments, the stamp device (e.g.stamp) (or, more precisely, the imprint pattern of the stamp device(e.g. stamp)) may be configured such that the lower end of the stampdevice (e.g. stamp) may reach the trench bottom. In this case, at leastparts of the bottom of the trench may be free from imprint materialafter embossing. Therefore, a mask structure that may be formed by theembossed imprint material may cover parts of the bottom of the trench inthis case.

In accordance with some embodiments, the imprint pattern of the stampdevice (e.g. stamp) may have any shape that allows removal of the stampdevice (e.g. stamp) from the trench without damaging a mask structure ormask pattern that may have been formed from the embossed (and possiblyhardened) imprint material, illustratively any shape that allowsembossing the imprint material such that the stamp device (e.g. stamp)(or, more precisely, its imprint structure or pattern) does not getcaught or stuck in the embossed (and, possibly, hardened) imprintmaterial.

Illustratively, in accordance with some embodiments, embossing imprintmaterial in a trench and, possibly, over the substrate surface using astamp device (e.g. stamp) may include patterning the imprint material tohave a pattern that corresponds to a 3D mask structure to be formed inthe trench and, possibly, over the substrate surface. In other words, a3D mask structure may be obtained by embossing a stamp device (e.g.stamp) having an imprint pattern that corresponds to the inverse (ornegative) of the 3D mask structure onto the imprint material.

In accordance with some embodiments, the 3D mask structure may be usedfor subsequent patterning processes, e.g. pattern plating processes, toobtain a three-dimensional (3D) pattern or structure such as, forexample, a three-dimensional (3D) metallization structure or pattern, aswill be described below.

In accordance with some embodiments, the stamp device (e.g. stamp) mayinclude or may be made of a material that may be harder than the imprintmaterial. In other words, in accordance with an embodiment the stampdevice's material or materials may have a higher mechanical hardnessthan the imprint material.

In accordance with an embodiment, the stamp device (e.g. stamp) mayinclude or may be made of a metal or a metal alloy (for example, similarto stamps used in audio compact disc (CD) production, in accordance withan embodiment). In accordance with an embodiment, the stamp device (e.g.stamp) may include or may be made of steel.

In accordance with an embodiment, the stamp device (e.g. stamp) mayinclude or may be made of a flexible material. For example, the stampdevice (e.g. stamp) may include or may be made of a polymer material,for example a silicone material in accordance with an embodiment,alternatively another polymer material. One effect of using a flexiblematerial such as, for example, a polymer material may be seen in that apossible occurrence of scratches in the imprint material as a result ofthe embossing (imprinting) may be avoided or reduced.

In accordance with an embodiment, the stamp device (e.g. stamp) mayinclude or may be made of a transparent material, for example in casethat the imprint material is a photosensitive material that may behardened by means of light irradiation. In accordance with anembodiment, the transparent material may for example be transparent forultraviolet (UV) radiation, e.g. in case that a UV sensitive (orcurable) material is used as imprint material. For example, inaccordance with some embodiments, the stamp device (e.g. stamp) mayinclude or may be made of a glass material, e.g. quartz glass materialin accordance with one embodiment.

In accordance with an embodiment, the stamp device (e.g. stamp) may beprovided (for example, fabricated or manufactured) using similar oranalog processes as in standard nanoimprint manufacturing.Alternatively, the stamp device (e.g. stamp) may be provided using othersuitable processes.

In accordance with some embodiments, in case that the imprint materialis also deposited over the substrate surface, embossing the imprintmaterial using the stamp device (e.g. stamp) may further includeembossing the imprint material deposited over the substrate surfaceusing the stamp device (e.g. stamp). Illustratively, in accordance withan embodiment, the stamp device (e.g. stamp) may have an imprint patternthat may be suitable for embossing structures in the trench and over thesubstrate surface.

In accordance with some embodiments, in case that the imprint materialis a hardenable material the imprint material may be hardened afterembossing the imprint material and before removing the stamp device(e.g. stamp) from the trench (see below).

For example, in case that a curable material such as, for example, acurable polymeric or polymerizable material (e.g. polymeric resistmaterial, e.g. photo resist) is used, hardening the imprint material mayinclude curing the imprint material. Illustratively, curing the imprintmaterial may include cross-linking of polymer chains of the imprintmaterial, as mentioned above.

In accordance with an embodiment, curing the imprint material (e.g.photosensitive resist material) may include exposing the imprintmaterial to light radiation, for example ultraviolet (UV) lightradiation (e.g. in case of an UV curable resist) in accordance with anembodiment.

In accordance with another embodiment, curing the imprint material (e.g.thermosensitive resist material) may include tempering the substrate(and thus the imprint material).

In accordance with another embodiment, curing the imprint material mayinclude applying micro-wave radiation to the imprint material. Forexample, in accordance with an embodiment, the imprint material mayinclude a matrix material, which may be a thermosensitive material, e.g.a thermosensitive polymer material, that may include nanoferriteparticles that may be embedded in the matrix material. The nanoferriteparticles may absorb energy from the electromagnetic field of themicro-wave radiation. This may lead to a heating of the nanoferriteparticles in the matrix material. In this manner, heat from the embeddednanoferrite particles may be released directly and locally in the matrixmaterial and the matrix material (e.g. polymer material) may be cured bythe released heat.

In 108, the stamp device (e.g. stamp) may be removed from the trench.

Illustratively, in accordance with some embodiments, a three-dimensional(3D) mask structure may remain in the trench and, in accordance withsome embodiments, over at least a part of the substrate surface afterremoval of the stamp device (e.g. stamp). The 3D mask structure maycorrespond to the patterned or structured (and, possibly, hardened orcured) imprint material (e.g. imprint resist).

In accordance with an embodiment, a flash and/or recess step may beperformed after removal of the stamp device (e.g. stamp). The flashand/or recess step may, for example, be used to remove possible imprintmaterial remainders (for example, thin polymer films, e.g. resist films)at e.g. sidewalls of the trench.

In accordance with an embodiment, filling material may be deposited intothe trench after removal of the stamp device (e.g. stamp). In accordancewith an embodiment, the filling material may be deposited after theflash and/or recess step (if provided).

In accordance with an embodiment, depositing the filling material mayinclude filling at least parts of the trench that are free from theimprint material. Illustratively, the filling material may fill (atleast partially) those parts of the trench that were occupied by thestamp device (e.g. stamp).

Illustratively, in accordance with some embodiments, depositing thefilling material may include filling “non-imprint-material areas” in thetrench, for example non-resist areas in case that a resist material isused as imprint material.

In accordance with some embodiments, the filling material may include ormay be electrically conductive material such as, for example, metal. Inaccordance with an embodiment, the filling material may include or maybe a metal, such as for example copper (Cu), alternatively any othersuitable metal or metal alloy.

In accordance with an embodiment, depositing the filling material (e.g.metal) may include or may be accomplished by galvanic deposition of thefilling material.

In accordance with an embodiment, depositing the filling material (e.g.metal) may include or may be accomplished by a plating process. In otherwords, the filling material (e.g. metal) may be deposited using aplating process (e.g. Cu plating).

Illustratively, in accordance with some embodiments, a 3D pattern orstructure (e.g. 3D plating pattern or structure) may be formed by thefilling material (e.g. metal). The 3D pattern or structure mayillustratively correspond to the imprint pattern of the stamp.

In accordance with an embodiment, at least one additional trench may beformed in the substrate, the imprint material may be deposited into theat least one additional trench, the imprint material may be embossedusing the stamp device (e.g. stamp), and the stamp device (e.g. stamp)may be removed from the at least one additional trench.

In accordance with an embodiment, embossing the imprint material in theat least one additional trench may be carried out after embossing theimprint material in the trench. Illustratively, in accordance with thisembodiment, the substrate may be processed in a “step and repeat”sequence where the stamp device (e.g. stamp) may sequentially emboss theimprint material in a plurality of trenches.

In accordance with another embodiment, embossing the imprint material inthe at least one additional trench and embossing the imprint material inthe trench may be carried out simultaneously. Illustratively, inaccordance with this embodiment, the substrate may be processed in an“all in one” manner where the stamp device (e.g. stamp) may emboss theimprint material in all of the trenches simultaneously (in other words,at once). In this case, the stamp device (e.g. stamp) may be configuredin a suitable manner, for example such that it includes a plurality ofimprint patterns (for example, one imprint pattern per trench). Inaccordance with an embodiment, the imprint patterns may all have thesame shape, alternatively, they may have different shapes. Furthermore,in accordance with an embodiment, if hardening of the imprint materialis provided, the imprint material in all of the trenches may be hardenedsimultaneously.

FIG. 2 is a diagram illustrating a method 200 of processing a substratein accordance with another embodiment.

In accordance with an embodiment, the substrate may be a semiconductorsubstrate, in other words a substrate that may include or may be made ofone or more semiconducting materials. For example, the substrate mayinclude or may be made of silicon (Si), alternatively any other suitablesemiconductor material such as e.g. germanium (Ge), a IV-IV compoundsemiconductor (e.g. SiGe), a III-V compound semiconductor (e.g. GaAs), aII-VI compound semiconductor (e.g. CdTe), or any other suitablesemiconductor material.

In accordance with an embodiment, the substrate may be or may include awafer, or may be part of a wafer, for example a semiconductor wafer suchas for example a silicon wafer, alternatively any other suitablesemiconductor wafer.

In accordance with another embodiment, the substrate may be or mayinclude a printed circuit board (PCB).

In 202, a trench may be formed in the substrate. The trench may beformed and/or configured in accordance with one or more embodimentsdescribed herein, for example by means of a trench process or by meansof a cutting process, alternatively using any other suitable trenchforming process.

In accordance with an embodiment, a bather layer may be deposited. Thebather layer may be deposited before disposing a stamp in the trench(see below). Furthermore, the bather layer may be deposited and/orconfigured in accordance with one or more embodiments described herein.

In accordance with an embodiment, a seed layer may be deposited. Theseed layer may be deposited before disposing a stamp device (e.g. stamp)in the trench (see below). Furthermore, the seed layer may be configuredin accordance with one or more embodiments described herein.

In 204, a stamp device (e.g. stamp) may be disposed at least in thetrench. The stamp device (e.g. stamp) may be configured in accordancewith one or more embodiments described herein. For example, the stampdevice may be configured as an imprint stamp that may include an imprintpattern in accordance with one or more embodiments described herein.

In 206, at least one part of the trench that is free from the stampdevice (e.g. stamp) (e.g. one or more parts of the trench that are freefrom the imprint pattern of the stamp device (e.g. stamp)) may be filledat least partially with trench filling material. In other words, one ormore “non-stamp” areas in the trench (i.e., areas of the trench that arefree from the stamp device's imprint pattern when the stamp device (e.g.stamp) is disposed in the trench) may illustratively be filled with thetrench filling material.

In accordance with some embodiments, the trench filling material mayinclude or may be a hardenable material, for example a hardenablematerial in accordance with any of the embodiments described herein, forexample a polymerizable material such as, for example, a curable polymerresist, e.g. a photo resist.

In accordance with some embodiments, the trench filling material may bedeposited such that also parts over the substrate surface that are freefrom the stamp device (e.g. stamp) (“non-stamp areas” over the substratesurface) are filled with the trench filling material. For example, inaccordance with some embodiments the trench filling material may bedeposited such that parts or regions over the substrate surface that arelocated between the substrate surface and an upper part of the stampdevice (e.g. stamp) may be filled with the trench filling material.

In accordance with an embodiment, in case that the trench fillingmaterial includes or is a hardenable material, the trench fillingmaterial may be deposited while it is in the non-hardened state.

In accordance with another embodiment, in case that the trench fillingmaterial includes or is a hardenable material, the trench fillingmaterial may be hardened after filling the trench and before removingthe stamp device (e.g. stamp) from the trench (see below). The hardeningof the trench filling material may be achieved in accordance with one ormore embodiments described herein.

In 208, the stamp device (e.g. stamp) may be removed from the trench.

Illustratively, in accordance with some embodiments, a 3D mask structuremay remain in the trench and, in accordance with some embodiments, overat least a part of the substrate surface when the stamp device (e.g.stamp) is removed from the trench. Illustratively, the 3D mask structuremay correspond to the patterned or structured (and, possibly, hardenedor cured) trench filling material (e.g. resist material).

In accordance with an embodiment, a flash and/or recess step may beperformed after removal of the stamp device (e.g. stamp). The flashand/or recess step may, for example, be used to remove possible trenchfilling material remainders (for example, thin polymer films, e.g.resist films) at e.g. sidewalls of the trench.

In accordance with an embodiment, filling material may be deposited intothe trench after removal of the stamp device (e.g. stamp). In accordancewith an embodiment, the filling material may be deposited after theflash and/or recess step (if provided). Depositing the filling materialmay be achieved in accordance with one or more embodiments describedherein. Furthermore, the filling material may be configured inaccordance with one or more embodiments described herein. For example,in accordance with one embodiment, the filling material may include ormay be electrically conductive material, for example metal (e.g. copper)that may serve to form one or more metallization structures.

In accordance with an embodiment, at least one additional trench may beformed in the substrate, the stamp device (e.g. stamp) may be disposedin the at least one additional trench, parts of the at least oneadditional trench that are free from the stamp device (e.g. stamp) maybe filled with the trench filling material, and the stamp device (e.g.stamp) may be removed from the at least one additional trench.

In accordance with an embodiment, disposing the stamp device (e.g.stamp) in the at least one additional trench and filling the parts ofthe at least one additional trench with the trench filling material maybe carried out after disposing the stamp device (e.g. stamp) in thetrench and filling the parts of the trench with the trench fillingmaterial. Illustratively, in accordance with this embodiment, thesubstrate may be processed in a “step and repeat” sequence where thestamp device (e.g. stamp) may be sequentially disposed in a plurality oftrenches.

In accordance with another embodiment, disposing the stamp device (e.g.stamp) in the at least one additional trench and disposing the stampdevice (e.g. stamp) in the trench may be carried out simultaneously.Furthermore, in accordance with an embodiment, filling the parts of theat least one additional trench and filling the parts of the trench withthe trench filling material may be carried out simultaneously.Illustratively, in accordance with this embodiment, the substrate may beprocessed in an “all in one” manner where e.g. the stamp device (e.g.stamp) may be simultaneously (in other words, at once) disposed in allof the trenches and/or the trenches may be filled simultaneously withthe trench filling material. In this connection, the stamp device (e.g.stamp) may be configured in a suitable manner, for example, in anembodiment, having a plurality of imprint patterns as described above inconnection with FIG. 1. Furthermore, in accordance with an embodiment,if hardening of the trench filling material is provided, the trenchfilling material in all of the trenches may be hardened simultaneously.

In a method of processing a substrate (for example a semiconductorsubstrate such as e.g. a wafer, e.g. a silicon wafer) in accordance withan embodiment a trench may be formed in the substrate (for example, bymeans of a trench etch process), imprint material may be deposited overthe substrate, thereby filling the trench at least partially with theimprint material, the imprint material in the trench may be embossed bymeans of an imprint stamp having an imprint pattern reaching at leastpartially into the trench, and the imprint stamp may be removed from thetrench. In accordance with an embodiment, the imprint material may be animprint resist such as, for example, a polymer resist, e.g. a photoresist. In accordance with an embodiment, the imprint pattern maycorrespond to the inverse of a three-dimensional mask structure to beformed by the imprint material, and the embossed imprint material mayhave a pattern that may correspond to the three-dimensional maskstructure. In accordance with an embodiment, the imprint material mayinclude or may be a hardenable material (e.g. a curable polymer materialsuch as, for example, a polymer resist, e.g photo resist) and may behardened (for example cured, e.g. by means of light irradiation, e.g. UVlight irradiation) after embossing and before removal of the stamp. Inaccordance with an embodiment, filling material may be deposited overthe substrate after the removal of the stamp, thereby filling at leastparts of the trench that are free from the imprint material. Inaccordance with an embodiment, the filling material may include or maybe electrically conductive material such as, for example, metal (e.g.copper).

In a method of processing a substrate (for example a semiconductorsubstrate such as e.g. a wafer, e.g. a silicon wafer) in accordance withanother embodiment, a trench may be formed in the substrate (forexample, by means of a trench etch process), an imprint stamp having animprint pattern may be disposed over the substrate such that the imprintpattern reaches at least partially into the trench, parts of the trenchthat are free from the imprint pattern of the imprint stamp may befilled at least partially with trench filling material, and the imprintstamp may be removed from over the substrate. In accordance with anembodiment, the imprint pattern may correspond to the inverse of athree-dimensional mask structure to be formed by the trench fillingmaterial, and after filling the parts of the trench with the trenchfilling material, the trench filling material may have a pattern thatmay correspond to the three-dimensional mask structure. In accordancewith an embodiment, the trench filling material may include or may be ahardenable material (e.g. a curable polymer material such as, forexample, a polymer resist, e.g photo resist) and may be hardened (forexample cured, e.g. by means of light irradiation, e.g. UV lightirradiation) after filling the parts of the trench with the trenchfilling material and before removal of the imprint stamp. In accordancewith an embodiment, filling material may be deposited over the substrateafter the removal of the imprint stamp, thereby filling at least partsof the trench that are free from the trench filling material. Inaccordance with an embodiment, the filling material may include or maybe electrically conductive material such as, for example, metal (e.g.copper).

FIG. 3 shows a perspective view of an exemplary three-dimensional (3D)structure 300 (also referred to as target structure) that may beobtained by means of a method of processing a substrate in accordancewith an embodiment.

The structure 300 includes a substrate 301. The substrate 301 may be asemiconductor substrate, e.g. a silicon (Si) substrate in accordancewith an embodiment. For example, the substrate 301 may be part of asilicon wafer in accordance with an embodiment.

A trench 302 is formed in the substrate 301, as shown. The trench 302may have been formed, for example, by means of an etch process, or bymeans of a cutting process in accordance with an embodiment,alternatively by means of any other suitable trench formation process.

A depth of the trench 302 (illustratively, a distance from a trenchbottom 314 to an upper substrate surface 301 a) is indicated by doublearrow 302 a in FIG. 3. In accordance with some embodiments, the trenchdepth 302 a may be smaller than the thickness of the substrate 301 (e.g.wafer). In accordance with some embodiments, the trench depth 302 a maybe in the micrometer range. For example, the trench depth 302 a may havea value of one or several micrometers, or of several tens of micrometersor of several hundreds of micrometers. For example, in accordance withsome embodiments, the trench depth 302 a may be in the range from about100 μm to about 300 μm, for example about 300 μm in accordance with oneembodiment. In accordance with other embodiments, the trench depth 302 amay have different values.

A width of the trench 302 (illustratively, a distance of opposingsidewalls 312 of the trench 302) is indicated by double arrow 302 b inFIG. 3. In accordance with some embodiments, the trench width 302 b maybe in the micrometer range. For example, in accordance with someembodiments, the trench width 302 b may be in the range from about 10 μmto about 200 μm, for example about 50 μm in accordance with oneembodiment. In accordance with other embodiments, the trench width 302 bmay have different values.

In accordance with other embodiments, three-dimensional structures withother geometries (e.g. other trench geometries) may be realized in asimilar manner as the structure 300 shown in FIG. 3. These structuresmay have similar or different dimensions, for example similar ordifferent trench dimensions, e.g. similar or different trench depthsand/or trench widths.

The target structure 300 further includes a three-dimensional (3D) maskstructure 303 that is formed in the trench 302 and over parts of thesubstrate 301 (more precisely, over parts of the upper surface 301 a ofthe substrate 301).

The mask structure 303 may include or may be made of an imprint materialsuch as, for example, an imprint resist (e.g. polymeric resist). Inaccordance with some embodiments, the mask structure 303 may have beenobtained by depositing the imprint material into the trench 302 andembossing the imprint material using a stamp device (for example, astamp or imprint stamp) that has an imprint pattern corresponding to theinverse of the mask structure 303.

Alternatively, the mask structure 303 may have been obtained bydisposing a stamp device (e.g. a stamp or imprint stamp) in the trench302 and over the upper surface 301 a of the substrate 301 and filling atleast parts of the trench 302 that are free from the stamp device (e.g.a stamp or imprint stamp) with trench filling material (for example,hardenable material such as a polymeric resist).

As shown, the mask structure 303 may include a first portion 303′ thatmay be located in the trench 302 and may cover the bottom 314 of thetrench 302, as shown. As shown, a width of the first portion 303′ of themask structure 303 may be the same as the width 302 b of the trench 302.In other words, the first portion 303′ may abut the sidewalls 312 of thetrench 302.

In accordance with some embodiments, a thickness of the first portion303′ of the mask structure 303 may be in the micrometer range, forexample on the order of several micrometers or several tens of amicrometer in accordance with one embodiment. In accordance with otherembodiments, the thickness may have different values.

In FIG. 3, double arrow 303 a indicates a distance between an uppersurface 313 of the first portion 303′ of the mask structure 303 and theupper surface 301 a of the substrate 301. Illustratively, the distance303 a may correspond to the trench depth 302 a minus the thickness ofthe first portion 303′ of the mask structure 303 and may be in themicrometer range, for example on the order of several tens or severalhundreds of a micrometer. For example, in accordance with an exemplaryembodiment, the distance 303 a may be about 250 μm. In accordance withother embodiments, the distance 303 a may have different values.

In accordance with the embodiment shown, the mask structure 303 mayfurther include a second portion 303″ that may be located in the trench302 and may have a width (indicated by double arrow 303 b in FIG. 3)that may be smaller than the width 302 b of the trench 302 such thatportions of the trench 302 are free from material of the mask structure303. Illustratively, a middle portion (second portion 303″) of the maskstructure 303 may have a bar shape or ridge shape in accordance with theembodiment shown in FIG. 3. A part of the second portion 303″ of themask structure 303 may protrude from the trench 302 in accordance withthe embodiment shown.

In accordance with the embodiment shown, the mask structure 303 mayfurther include a third portion 303′″ that may cover parts of thesubstrate 301 (more precisely, parts of the upper surface 301 a of thesubstrate 301).

The first portion 303′ of the mask structure 301 that covers the bottom314 of the trench 302 may serve to prevent filling material (e.g.electrically conductive material such as, for example, metal that may befilled into the trench 302 after the mask structure 303 has been formed,as will be described below) from reaching the bottom 314 of the trench302. In accordance with another embodiment, the first portion 303′ maynot be present or may have a smaller width than the trench (for example,the same width as the second portion 303″ of the mask structure 303)(not shown). Thus, in accordance with this embodiment, at least parts ofthe bottom 314 of the trench 302 may be free from material of the maskstructure 303. In this case, filling material (e.g. electricallyconductive material such as, for example, metal) that may be filled intothe trench 302 after the mask structure 303 has been formed may reachthe bottom 314 of the trench 302.

Illustratively, FIG. 3 shows an exemplary three-dimensional (target)structure 300 including a three-dimensional (3D) mask structure 303. Inorder to obtain the target structure 300, material (e.g. resist) formingthe mask structure 303 needs to be structured not only on top of thesubstrate surface 301 a but also in the trench 302. In accordance withsome embodiments, the structured or patterned mask structure 303 may beachieved by means of depositing imprint material (e.g. imprint resist)in the trench 302 and over the substrate surface 301 a and embossing theimprint material with a stamp device (e.g. a stamp or imprint stamp)having a three-dimensional (3D) imprint pattern that corresponds to theinverse of the 3D mask structure 303, as will be described furtherbelow. In accordance with other embodiments, the structured or patternedmask structure 303 may be achieved by means of disposing a stamp device(e.g. imprint stamp) in the trench 302 and over the substrate surface301 a and subsequently filling parts of the trench 302 and over thesubstrate surface 301 a that are free from the stamp device (e.g. stampor imprint stamp) with trench filling material (e.g. hardenable materialsuch as, for example, resist).

It is noted that forming 3D target structures such as the structure 300shown in FIG. 3 may not be possible at all or may be comparativelycostly (e.g. require a high number of process steps) using conventionalapproaches. For example, standard lithography may fail as the requiredresist thicknesses cannot be exposed accordingly (e.g. due toinsufficient depth of focus of the exposure tools, occurrence of straylight at edges, instability of the resist wall(s) due to solvent lossduring bake-out processes, etc.). On the other hand, two-photonlithography may fail as the structure in the deep trench cannot beaccessed. Finally, standard nano-imprint processes may not be used asthey are designed for printing structures on plain surfaces only.

FIG. 4 shows a schematic perspective view of a stamp device 400 that maybe used in a method of processing a substrate. In accordance with theembodiment shown, the stamp device 400 is configured as a stamp. Thestamp device 400 or stamp 400 may be used to obtain thethree-dimensional target structure 300 of FIG. 3.

The stamp 400 may be configured as an imprint stamp and may include ormay be made of a material that may be suited to emboss the material(e.g. imprint resist) of the mask structure 303. In accordance with oneembodiment, the stamp 400 may be made of a transparent material, e.g. ofa UV transparent material, for example in case that an imprint materialthat is to be embossed by the stamp 400 is configured as a hardenablematerial that may be hardened by means of irradiation (e.g. UVirradiation). In accordance with other embodiments, the stamp 400 mayinclude or may be made of other materials, for example a flexiblematerial such as, for example, a polymer material (e.g. a siliconematerial) in accordance with one embodiment, or a metal or metal alloy.

In accordance with the embodiment shown, the stamp 400 may include aplanar upper portion 401 that may correspond to a base-mask.Furthermore, the stamp 400 may include an imprint pattern 402 thatillustratively corresponds to an inverse (or negative) of the 3D maskstructure 303 shown in FIG. 3.

In accordance with the embodiment shown, the imprint pattern 402includes two L-shaped portions 402′ and 402″ arrangedmirror-symmetrically and configured in such a manner that the 3D maskstructure 303 of FIG. 3 may be obtained by embossing imprint material inthe trench 302 and over the substrate surface 301 a using the stamp 400or by filling parts of the trench 302 and over the substrate surface 301a that are free from the imprint pattern 402 with trench-fillingmaterial, as will be described below.

It is noted that, in accordance with other embodiments, the imprintpattern of a stamp device (e.g. of a stamp, or of a roll) may have ashape that may be different from the one shown in FIG. 4. For example,the imprint pattern may not need to have the two L-shaped portions shownin FIG. 4. In general, the shape of the imprint pattern of a stampdevice (e.g. of a stamp, or of a roll) may depend on thethree-dimensional mask structure or target structure to be formed usingthe stamp device. For example, in accordance with some embodiments, anyshape or pattern that is free from undercuts (in other words, that doesnot have any undercuts) may be suitable for use as imprint pattern.

In accordance with the embodiment shown, each of the two L-shapedportions 402′, 402″ of the imprint pattern 402 includes a verticalsection 422 (extending in a direction perpendicular to the main surfaceof the base-mask) with an extension (denoted by double arrow 403 a) thatcorresponds to the distance 303 a shown in FIG. 3. The vertical sections422 may reach into the trench 302 when the stamp 400 is used forembossing the imprint material in the trench 302 (see e.g. FIG. 5D) orwhen the stamp 400 is disposed in the trench 302 before depositing thetrench filling material (see e.g. FIG. 9C). Furthermore, a distance 403b between the two L-shaped portions 402′, 402″ corresponds to the width303 b of the second portion 303″ of the 3D mask structure 303 (see e.g.FIG. 5D and FIG. 9D). Furthermore, a distance 402 b between respectiveouter sidewalls 415 of the two L-shaped portions 402′, 402″ of theimprint pattern 402 corresponds to the width 302 b of the trench 302(see e.g. FIG. 5D and FIG. 9C). In other words, the value of thedistance 402 b may be the same or approximately the same as the value ofthe trench width 302 b.

The two L-shaped portions 402′, 402″ of the imprint pattern 402 may alsobe referred to as micro-imprint structures (μ-imprint structures). Thestamp 400 may also be referred to as micro-imprint mask (μ-imprintmask).

In accordance with some embodiments, the 3D mask structure 303 shown inFIG. 3 may be obtained by embossing imprint material in the trench 302using the stamp 400 shown in FIG. 4, as will be described below inconnection with FIGS. 5A to 5E. In accordance with other embodiments,the 3D mask structure 303 shown in FIG. 3 may be obtained by disposingthe stamp 400 of FIG. 4 in the trench 302 and filling parts of thetrench 302 that are free from the stamp 400 with trench fillingmaterial, as will be described below in connection with FIGS. 9A to 9E.The 3D mask structure 303 may, for example, subsequently be used to formone or more 3D metallization structures, as will be described below inconnection with FIG. 5F and FIG. 5G. The metallization structures may,for example, be used for electrically contacting one or more electricalor electronic elements or devices of one or more dies or chips, as willbe described below in connection with FIGS. 6 to 8.

In the following, a method of processing a substrate in accordance withan embodiment is described in connection with FIGS. 5A to 5E, which showdifferent process stages as schematic cross-sectional views.

FIG. 5A shows in a first view 510 that a trench 302 is formed in asubstrate 301. The substrate 301 includes an upper surface 301 a and mayfurther be configured in accordance with one or more embodimentsdescribed herein, for example as a semiconductor substrate, for exampleas a wafer, e.g. as a silicon wafer.

The trench 302 may be formed in accordance with one or more embodimentsdescribed herein, for example using a standard trench etch process. Thetrench 302 includes sidewalls 312 and a bottom 314. A depth of thetrench 302 is indicated by double arrow 302 a and may, for example, havea value in accordance with one or more embodiments described herein.Furthermore, a width of the trench 302 is indicated by double arrow 302b and may, for example, have a value in accordance with one or moreembodiments described herein.

In accordance with an embodiment, a barrier layer may be deposited overat least the sidewalls 312 of the trench 302 (not shown). In accordancewith another embodiment, a seed layer may be deposited over the batherlayer (not shown). In accordance with other embodiments, the batherlayer and/or seed layer may be omitted.

FIG. 5B shows in a second view 520 that the substrate 301 (e.g. thewafer) is coated with a thick layer of imprint material (e.g. imprintresist) 521. As shown, the imprint material 521 may fill the trench 302and cover at least parts of the upper surface 301 a of the substrate301. The imprint material 521 may be patterned or structured byimprinting as will be described herein below. In accordance with someembodiments, the imprint material may be a hardenable material, forexample a curable polymeric material such as e.g. a polymer resist, forexample a photoresist that may be cured by means of irradiation (e.g. UVirradiation).

FIG. 5C shows in a third view 530 that the imprint material 521 isimprinted by embossing a stamp 400 onto the imprint material 521. Theembossing is indicated by arrow 531 in FIG. 5C. The stamp 400 may beconfigured in a similar manner as the stamp described herein above inconnection with FIG. 4. In particular, the same reference numerals maydenote the same elements as in FIG. 4. By means of embossing the stamp400 onto the imprint material 521 the imprint material 521 (e.g. imprintresist) may be patterned to form a three-dimensional mask structure 303as is shown in a fourth view 540 in FIG. 5D. The three-dimensional maskstructure 303 may have a similar shape as shown in FIG. 3. Inparticular, the same reference numerals may denote the same elements asin FIG. 3.

In accordance with some embodiments, the three-dimensional maskstructure 303 (more precisely, the imprint material 521 of thethree-dimensional mask structure 303) may be hardened after imprinting.In accordance with some embodiments, the hardening may be achieved bymeans of light irradiation (e.g. UV irradiation). In this case, thestamp 400 may be made of a light transparent (e.g. UV transparent)material in order to let the light (e.g. UV radiation) pass, and theimprint material 521 may be a material that may be hardened by means oflight irradiation (e.g. UV irradiation) such as, for example, aphotosensitive (e.g. UV sensitive) polymeric resist.

FIG. 5E shows in a fifth view 550 that the stamp 400 is removed from thetrench 302. As shown, the three-dimensional mask structure 303 includingthe first portion 303′ and the second portion 303″ remains in the trench302. It is noted that the three-dimensional mask structure 303 mayfurther include the third portion 303′″ that may cover parts of theupper surface 301 a of the substrate 301, which is shown in FIG. 3 butis not shown in FIG. 5E as the fifth view 550 clearly corresponds to across-section along the cross-sectional line A-A′ in FIG. 3.

Illustratively, in accordance with some embodiments, a three-dimensional(3D) stamp 400 may be embossed onto a substrate 301 coated with imprintmaterial 521 (e.g. imprint resist). In accordance with some embodiments,the imprint material 521 may be hardened after embossing and beforeremoval of the stamp 400. For example, in accordance with an embodimentwhere the imprint material 521 is a photosensitive resist material, theresist may be exposed to light in order to crosslink polymer chains inthe resist material. In this case, the stamp 400 may be configured as atransparent stamp to let pass the light used for exposure of the resist.In accordance with other embodiments, crosslinking (or change ofsolubility) of resist like polymers may also be achieved by applyingelevated temperatures or electrical voltages.

In accordance with an embodiment, a cleaning step such as, for example,a flash/recess step may be performed after removal of the stamp 400 toremove possible remainders of the imprint material 521 (e.g. thinpolymer films (e.g. resist films)) from e.g. the sidewalls 312 of thetrench 302.

In accordance with some embodiments, the three-dimensional (3D) maskstructure 303 (e.g. 3D polymer mask) may be used for subsequentmetallization processes such as pattern plating processes, where thenon-imprint-material areas (clearly, those parts of the trench 302 andover the upper surface 301 a of the substrate 301 that are free fromimprint material 521) (i.e. non-resist areas in case that the imprintmaterial 521 is a resist material) may be galvanically filled with metal561 (e.g. copper (Cu)), as is shown in a sixth view 560 in FIG. 5F.

In accordance with the embodiment shown, the metal 561 extends into thetrench 302 up to the upper surface 313 of the first portion 303′ of themask structure 303, that is up to a depth 503 a that corresponds to thedistance 303 a, as is shown in FIG. 5F. Thus, in accordance with theembodiment shown, the metal 561 is spaced apart from the trench bottom314 by means of the first portion 303′ of the mask structure 303 thatcovers the trench bottom 314. In accordance with other embodiments, themask structure 303 may be configured such that the metal 561 reaches thetrench bottom 314.

After filling the non-imprint-material areas with the metal 561, the 3Dmask structure 303 may be removed (using, for example, a suitableprocess for selectively removing the material (e.g. resist) of the maskstructure 303 while the metal 561 remains in the trench 303 and over thesubstrate surface 301 a), as is shown in a seventh view 570 in FIG. 5G.The metal 561 may, for example, serve as one or more metallizationstructures to electrically contact one or more electrical and/orelectronic devices that may be or may have been formed in the substrate301, as is shown in FIG. 6.

FIG. 6 shows a schematic cross-sectional view 600 of a substrate 301 forillustrating formation of metallization structures using a method ofprocessing a substrate in accordance with an embodiment. The substrate301 may be a wafer or may be part of a wafer. A trench 302 has beenformed in the substrate 301, and a first metallization structure 610 aand a second metallization structure 610 b have been formed in thetrench 302 and over the upper surface 301 a of the substrate 301. Thetrench 302 and the first and second metallization structures 610 a, 610b may have been formed by means of a method of processing a substrate inaccordance with one or more embodiments described herein, for example ina similar manner as described above in connection with FIG. 5A to FIG.5G. The first metallization structure 610 a serves to electricallycontact at least one first electronic device 602 a that is located inthe substrate 301. The second metallization structure 610 b serves toelectrically contact at least one second electronic device 602 b locatedin the substrate 301.

The at least one first electronic device 602 a may be located in a firstregion 603 of the substrate 301 that may correspond to a first die to beformed from the substrate 301, and the at least one second electronicdevice 602 b may be located in a second region 604 of the substrate 301that may correspond to a second die to be formed from the substrate 301,as shown. The first region 603 and the second region 604 of thesubstrate 301 may be located adjacent to one another and may be joinedby a third region 605 of the substrate 301 located between the firstregion 603 and the second region 604 of the substrate 301 and betweenthe bottom 314 of the trench 302 and a lower surface 301 b of thesubstrate 301, as shown. In accordance with an embodiment, the first dieand the second die may be obtained using a die singulation process. Inother words, the first region 603 and the second region 604 of thesubstrate 301 may be separated from one another (for example, by meansof a die cutting process) thereby removing the third region 605 (that isthe linking part) between the first region 603 and the second region 604of the substrate 301.

In addition to the trench 302 and the first and second metallizationstructures 610 a, 610 b shown in FIG. 6, additional trenches (not shown)may have been formed in the substrate 301 and additional metallizationstructures (not shown) may have been formed in the additional trenchesand over the upper surface 301 a of the substrate 301 in a similarmanner as the trench 302 and the first and second metallizationstructures 610 a, 610 b. The additional metallization structures mayserve to electrically contact the first electronic device 602 a and/orthe second electronic device 602 b and/or additional electronic devicesthat may, for example, be located in additional regions of the substrate301 that may correspond to additional dies to be formed from thesubstrate 301. The additional dies may, for example, be obtained using adie singulation process, in which the additional regions of thesubstrate may be separated from one another (in other words, the diesmay be singulated).

Thus, illustratively, in accordance with some embodiments, a diearrangement or die array including a plurality of dies (or chips) and aplurality of die metallization structures to electrically contact thedies may be provided as is shown in FIG. 7.

FIG. 7 shows a schematic top view of a die array 750 for illustratingformation of die metallization structures using a method of processing asubstrate in accordance with an embodiment. The die array 750 includes aplurality of dies (chips) 700 arranged in rows 720, 740, 760 and columns725, 745, 765, 785 (in this example, twelve dies 700 are arranged in arectangular array including a first row 720, a second row 740, and athird row 760, and a first column 725, a second column 745, a thirdcolumn 765, and a fourth column 785; in general, an arbitrary number ofdies 700 may be arranged in an arbitrary number of rows and columns).The dies 700 may have been obtained from a common substrate 301 (e.g. awafer) by means of die singulation. Each die 700 includes a plurality ofdie metallization structures 710 a, 710 b, 710 c, 710 d. In the exampleshown, a first die metallization structure 710 a, a second diemetallization structure 710 b, a third die metallization structure 710 cand a fourth die metallization structure 710 d are provided for each die700. As shown, each die 700 may have a rectangular (e.g. quadratic)shape including four side surfaces 700 a, 700 b, 700 c, 700 d, and thedie metallization structures 710 a, 710 b, 710 c, 710 d may be arrangedat the four side surfaces 700 a, 700 b, 700 c, 700 d of the die 700, asshown. In particular, the first die metallization structure 710 a andthe second die metallization structure 710 b are located at first andsecond side surfaces 700 a, 700 b of the die 700 that are opposite toone another, and the third die metallization structure 710 c and thefourth die metallization structure 710 d are located at third and fourthside surfaces 700 c, 700 d of the die 700 that are opposite to oneanother, as shown. In accordance with other embodiments, a differentnumber of die metallization structures per die may be provided and/orthe die metallization structures may be arranged differently. The diemetallization structures 710 a, 710 b, 710 c, 710 c may be used toelectrically contact one or more electronic devices of the respectivedie 700.

The die metallization structures 710 a, 710 b, 710 c, 710 d may havebeen formed by means of a method of processing a substrate in accordancewith one or more embodiments described herein, for example in a similarmanner as described above in connection with FIG. 5A to FIG. 5G.

Illustratively, the first die metallization structure 710 a of a givendie 700 and the second die metallization structure 710 b of anearest-neighbor die 700 in the same row may have been formed using acommon three-dimensional mask structure formed in a trench locatedbetween the two neighboring dies. For example, the first diemetallization structure 710 a of a first die 700′ of the plurality ofdies 700 that is located at the cross-point of the second row 740 withthe second column 745 and the second die metallization structure 710 bof a second die 700″ of the plurality of dies 700 that is located at thecross-point of the second row 740 with the first column 725 may havebeen formed using a common three-dimensional mask structure formed in atrench located between the two neighboring dies 700′, 700″.

Similarly, the third die metallization structure 710 c of a given die700 and the fourth die metallization structure 710 d of anearest-neighbor die 700 in the same column may have been formed using acommon three-dimensional mask structure formed in a trench locatedbetween the two neighboring dies. For example, the third diemetallization structure 710 c of the first die 700′ located at thecross-point of the second row 740 with the second column 745 and thefourth die metallization structure 710 d of a third die 700′″ located atthe cross-point of the first row 720 with the second column 745 may havebeen formed using a common three-dimensional mask structure formed in atrench located between the two neighboring dies 700′, 700′″.

Illustratively, the die array 750 shown in FIG. 7 is configured suchthat each die (chip) 700 of the plurality of dies 700 includes fourcontacts (e.g. pins).

FIG. 8 shows a schematic perspective view 800 of a die for illustratingformation of die metallization structures using a method of processing asubstrate in accordance with another embodiment.

The die 800 includes three die metallization structures 810 a, 810 b,810 c that are configured as surface and sidewall contacts. In otherwords, the die metallization structures 810 a, 810 b, 810 c are formedover the upper surface and the sidewalls of the die 800. The diemetallization structures 810 a, 810 b, 810 c may be formed by galvanicdeposition after structuring a three-dimensional mask (e.g. resist mask)using a method of processing a substrate in accordance with one or moreembodiments, for example in a similar manner as described above inconnection with FIGS. 5A to 5G.

Illustratively, FIG. 8 shows another example of a target product (i.e. adie with die metallizations) that may be obtained using a method ofprocessing a substrate in accordance with an embodiment.

In the following, a method of processing a substrate in accordance withanother embodiment is described in connection with FIGS. 9A to 9E, whichshow different process stages as schematic cross-sectional views.

FIG. 9A shows in a first view 910 that a trench 302 is formed in asubstrate 301. The substrate 301 includes an upper surface 301 a and mayfurther be configured in accordance with one or more embodimentsdescribed herein, for example as a semiconductor substrate, for exampleas a wafer, e.g. as a silicon wafer.

The trench 302 may be formed in accordance with one or more embodimentsdescribed herein, for example using a standard trench etch process. Thetrench 302 includes sidewalls 312 and a bottom 314. A depth of thetrench 302 is indicated by double arrow 302 a and may, for example, havea value in accordance with one or more embodiments described herein.Furthermore, a width of the trench 302 is indicated by double arrow 302b and may, for example, have a value in accordance with one or moreembodiments described herein.

In accordance with an embodiment, a bather layer may be deposited overat least the sidewalls 312 of the trench 302 (not shown). In accordancewith another embodiment, a seed layer may be deposited over the batherlayer (not shown). In accordance with other embodiments, the batherlayer and/or seed layer may be omitted.

FIG. 9B and FIG. 9C show in a second view 920 and a third view 930 thata stamp 400 including a three-dimensional imprint pattern 402 isdisposed in the trench 302 and over at least parts of the upper surface301 a of the substrate 301. FIG. 9B shows the stamp 400 before placementin the trench 302, the placement of the stamp 400 in the trench 302 isindicated by arrow 931. FIG. 9C shows the stamp 302 after placement inthe trench 302. The stamp 400 may be configured in a similar manner asdescribed herein above in connection with FIG. 4 and FIG. 5C. Elementswith the same reference numerals as in FIG. 4 or FIG. 5C are the sameand reference is made to the description above for the sake of brevity.

FIG. 9D shows in a fourth view 940 that parts of the trench 302 that arefree from the stamp 400 are filled with trench filling material 921. Inaccordance with some embodiments the trench filling material 921 may bea hardenable material (for example, a polymeric resist material) andmay, for example, be configured in accordance with one or moreembodiments described herein. For example, in accordance with someembodiments, the trench filling material 921 may include or may be apolymeric resist, for example a photosensitive polymer resist that maybe cured by exposure to light (e.g. UV radiation in case of a UVsensitive resist) in accordance with one embodiment, or athermosensitive polymer resist that may be cured by applying elevatedtemperatures in accordance with another embodiment, or a resist that maybe cured by applying an electrical voltage in accordance with stillanother embodiment.

In accordance with some embodiments, the trench filling material 921 mayalso cover parts of the upper surface 301 a of the substrate (not shownin FIG. 9D). Illustratively, the trench filling material 921 may form athree-dimensional (3D) mask structure 303 that may have a similar shapeas shown and described in connection with FIG. 3. Elements with the samereference numerals as in FIG. 3 are the same and reference is made tothe description above for the sake of brevity.

In accordance with some embodiments, the three-dimensional maskstructure 303 (more precisely, the trench filling material 921 of thethree-dimensional mask structure 303) may be hardened after depositionof the trench filling material 921. In accordance with some embodiments,the hardening may be achieved by means of light irradiation (e.g. UVirradiation). In this case, the stamp 400 may be made of a lighttransparent (e.g. UV transparent) material in order to let light (e.g.UV radiation) pass, and the trench filling material 921 may be amaterial that may be hardened by means of light irradiation (e.g. UVirradiation) such as, for example, a photosensitive (e.g. UV sensitive)polymeric resist.

FIG. 9E shows in a fifth view 950 that the stamp 400 is removed from thetrench 302. As shown, the three-dimensional mask structure 303 includingthe first portion 303′ and the second portion 303″ remains in the trench302. It is noted that the three-dimensional mask structure 303 mayfurther include a third portion 303′″ that may cover parts of the uppersurface 301 a of the substrate 301, as is shown in FIG. 3, but is notshown in FIG. 9E which may clearly correspond to a cross-sectional viewalong the cross-sectional line A-A′ in FIG. 3.

Illustratively, in accordance with some embodiments, a stamp 400including a three-dimensional (3D) imprint pattern may be disposed in atrench 302 in the substrate 301 such that the 3D pattern may reach atleast partially into the trench 302. Parts of the trench 302 that arefree from the stamp 400 may subsequently be filled with trench fillingmaterial 921 (e.g. hardenable material such as, for example, a polymerresist). In accordance with some embodiments, the trench fillingmaterial 921 may be hardened after deposition of the trench fillingmaterial 921 and before removal of the stamp 400. For example, inaccordance with an embodiment where the trench filling material 921 is aphotosensitive resist material, the resist may be exposed to light inorder to crosslink polymer chains in the resist material. In this case,the stamp 400 may be configured as a transparent stamp to let pass thelight used for exposure of the resist. In accordance with otherembodiments, crosslinking (or change of solubility) of resist likepolymers may also be achieved by applying elevated temperatures orelectrical voltages.

In accordance with an embodiment, a cleaning step such as, for example,a flash/recess step may be performed after removal of the stamp 400 toremove possible remainders of the trench filling material 921 (e.g. thinpolymer films (e.g. resist films)) from e.g. the sidewalls 312 of thetrench 302.

In accordance with some embodiments, the three-dimensional (3D) maskstructure 303 (e.g. 3D polymer mask) may, for example, be used forsubsequent metallization processes such as pattern plating processes, asdescribed above. For example, in accordance with some embodiments, thesubstrate 301 may be further processed in a similar manner as describedabove in connection with FIG. 5F and FIG. 5G and, in accordance withsome embodiments, the same or similar structures as shown in FIGS. 6 to8 may, for example, be obtained.

In the foregoing, various embodiments with a stamp device configured asa stamp have been described. In accordance with some embodiments, astamp device may, for example, also include or be configured as a(structured) roll. In other words, in accordance with some embodiments,a stamp device may include or may be a roll that may be structured suchthat it may include at least one imprint structure or pattern. Theimprint structure or pattern may, for example, be configured inaccordance with one or more embodiments described herein. A roll havingone or more imprint structures or patterns may for example be used forrolling over the substrate (for example, over a printed circuit board(PCB)).

FIG. 10 shows a schematic cross-sectional view of a stamp device 1000,which is configured as a roll and may be used in a method of processinga substrate in accordance with an embodiment. The stamp device 1000,i.e. the roll 1000, may be structured to include an imprint pattern 402,as shown, which may be used for embossing or imprinting in a trench. Theimprint pattern 402 may be configured in accordance with one or moreembodiments described herein. It is to be noted that in addition to theimprint pattern 402 shown in FIG. 10 the roll 1000 may includeadditional imprint patterns, in accordance with some embodiments. Theroll 1000 may be used for rolling over a substrate 301 (for example,over a printed circuit board (PCB) in accordance with an embodiment), asindicated by arrow 1050. The substrate 301 (e.g. PCB) may include atrench 302 (only one trench 302 is shown in FIG. 10; however, more thanone trench may be present in accordance with other embodiments). Thetrench 302 (or trenches) may have been formed, for example, inaccordance with one or more embodiments described herein. Furthermore,the trench 302 (or trenches) may have been filled with trench fillingmaterial 1021, as shown. The trench filling material 1021 may beconfigured in accordance with one or more embodiments described herein.When the roll 1000 rolls over the substrate 301 the imprint pattern 402of the roll 1000 may emboss the trench filling material 1021 in thetrench 302 resulting in a three-dimensional structure in the trench 302.Similarly, additional three-dimensional structures may be formed inadditional trenches in the substrate 301 (not shown) when the roll 1000continues rolling over the substrate 301.

A method of processing a substrate in accordance with an embodiment mayinclude: forming a trench in the substrate; depositing imprint materialat least into the trench; embossing the imprint material in the trenchusing a stamp device; and removing the stamp device from the trench.

In accordance with an embodiment, the stamp device may include or may bea stamp, for example an imprint stamp.

In accordance with another embodiment, the stamp device may include ormay be a roll.

In accordance with an embodiment, the substrate may include or may be asemiconductor substrate.

In accordance with another embodiment, the substrate may include or maybe a printed circuit board (PCB).

In accordance with another embodiment, the imprint material may includeor may be made of a hardenable material.

In accordance with another embodiment, the imprint material may behardened after embossing and before removal of the stamp device.

In accordance with another embodiment, the hardenable material mayinclude or may be made of a polymerizable material.

In accordance with another embodiment, hardening the imprint materialmay include at least one of: exposing the imprint material to light,tempering the substrate, applying an electrical voltage to the imprintmaterial.

In accordance with another embodiment, filling material may be depositedat least into the trench after removal of the stamp device.

In accordance with another embodiment, the filling material may includeor may be metal.

In accordance with another embodiment, depositing the filling materialmay include a plating process. In other words, depositing the fillingmaterial may be achieved using a plating process.

In accordance with another embodiment, the stamp device may include atleast one pattern suitable for embossing structures in the trench.

In accordance with another embodiment, the stamp device may include animprint pattern corresponding to a three-dimensional mask structure tobe formed at least in the trench.

In accordance with another embodiment, the stamp device may include ormay be made of metal.

In accordance with another embodiment, the stamp device may include ormay be made of a flexible material.

In accordance with another embodiment, the stamp device may include ormay be made of a transparent material, and hardening the imprintmaterial may include exposing the imprint material to light.

In accordance with another embodiment, at least one additional trenchmay be formed in the substrate, imprint material may be deposited intothe at least one additional trench, the imprint material in the at leastone additional trench may be embossed using the stamp device, and thestamp device may be removed from the at least one additional trench.

In accordance with another embodiment, embossing the imprint material inthe at least one additional trench may be carried out after embossingthe imprint material in the trench.

In accordance with another embodiment, embossing the imprint material inthe at least one additional trench and embossing the imprint material inthe trench may be carried out simultaneously.

In accordance with another embodiment, depositing the imprint materialat least into the trench may further include depositing the imprintmaterial over at least a part of the substrate surface, and embossingthe imprint material using the stamp device may further includeembossing the imprint material deposited over the substrate surface.

A method of processing a substrate in accordance with another embodimentmay include: forming a trench in the substrate; disposing a stamp deviceat least in the trench; filling at least one part of the trench that isfree from the stamp device at least partially with trench fillingmaterial; and removing the stamp device from the trench.

In accordance with an embodiment, the stamp device may include or may bea stamp, for example an imprint stamp.

In accordance with another embodiment, the stamp device may include ormay be a roll.

In accordance with an embodiment, the trench filling material mayinclude or may be a hardenable material, and the trench filling materialmay be hardened after filling the parts of the trench with the trenchfilling material and before removing the stamp device from the trench.

In accordance with another embodiment, hardening the trench fillingmaterial may include at least one of: exposing the trench fillingmaterial to light; tempering the substrate; applying an electricalvoltage.

In accordance with another embodiment, filling material may be depositedat least into the trench after removal of the stamp device.

In accordance with another embodiment, the filling material may includeor may be metal.

In accordance with another embodiment, depositing the filling materialmay include a plating process. In other words, depositing the fillingmaterial may be achieved using a plating process.

In accordance with another embodiment, the stamp device may include animprint pattern corresponding to a three-dimensional mask structure tobe formed at least in the trench.

In accordance with another embodiment, the stamp device may include ormay be made of metal.

In accordance with another embodiment, the stamp device may include ormay be made of a flexible material.

In accordance with another embodiment, the stamp device may include ormay be made of a transparent material; and hardening the trench fillingmaterial may include exposing the trench filling material to light.

In accordance with another embodiment, at least one additional trenchmay be formed in the substrate; the stamp device may be disposed atleast in the at least one additional trench; at least one part of the atleast one additional trench that is free from the stamp device may befilled at least partially with the trench filling material; and thestamp device may be removed from the at least one additional trench.

A method of processing a substrate in accordance with another embodimentmay include: forming a trench in the substrate; depositing imprintmaterial over the substrate, thereby filling the trench at leastpartially with the imprint material; embossing the imprint material inthe trench by means of an imprint stamp having an imprint pattern thatcorresponds to an inverse of a mask structure, thereby forming the maskstructure at least in the trench; hardening the embossed imprintmaterial; and removing the imprint stamp from the trench.

In accordance with an embodiment, hardening the embossed imprintmaterial may include at least one of: exposing the imprint material tolight; tempering the substrate; applying an electrical voltage to theimprint material.

In accordance with another embodiment, the imprint material may includeor may be made of a photosensitive imprint resist, and hardening theembossed imprint material may include exposing the imprint material tolight.

In accordance with another embodiment, the imprint material may includeor may be made of imprint resist.

In accordance with another embodiment, the imprint stamp may include ormay be made of a transparent material.

In accordance with another embodiment, filling material may be depositedover the substrate after removal of the imprint stamp, thereby fillingat least those parts of the trench that are free from the embossedimprint material with the filling material.

In accordance with another embodiment, the filling material may includeor may be made of metal.

In the following, certain features, aspects and effects of exemplaryembodiments are described.

In accordance with some embodiments, imprint-like processes forthree-dimensional (3D) structuring are provided.

In accordance with some embodiments, a modified imprint step may beused, where a stamp device (e.g. imprint stamp) may be also used todefine structures in the third dimension (for example, inside a trench).

In accordance with some embodiments, a stamp that may be used for“macro-imprint” may be designed with patterns suitable for embossingstructures in a deep trench.

In accordance with some embodiments, processes are provided that mayinclude printing on non-planar surfaces (for example, on surfaces thatmay have one or more trenches (e.g. deep trenches) or recesses).

In accordance with some embodiments, processes are provided that mayinclude “one step” structuring at two or more topography levels, therebygenerating three-dimensional patterns.

In accordance with some embodiments, processes are provided that may usea stamp (or stamps) that may have a pattern (or patterns) not only forprinting structures on planar surfaces (e.g. planar wafer surfaces) butalso a pattern (or patterns) for embossing structures in a thirddimension (e.g. inside a trench).

Effects of certain embodiments may be or may include:

-   -   3D structuring may be achieved using a lower number of process        steps (e.g. compared to multi-step lithography processes) and/or    -   3D structuring may be achieved at lower costs (e.g. avoiding        costly processes such as two-photon absorption or expensive        tools).

In accordance with some embodiments, 3D target structures may berealized that may not (or only with comparatively high complexity and/orcosts) be achieved using standard processes such as e.g. standardlithography processes. For example, in accordance with some embodiments3D mask structuring in a deep substrate trench may be achieved. In thiscase, standard lithography would face serious problems (resistthickness, depth of focus not sufficient, occurrence of stray light atedges, instability of the resist wall(s) due to solvent loss at bakes,limitations regarding slope of side walls, etc.) or even fail. On theother hand, two-photon lithography would also fail as the structure inthe deep trench could not be accessed. Finally, standard nano-imprintprocesses could not be used as they are designed for printing structureson plain surfaces only.

While the invention has been particularly shown and described withreference to specific embodiments, it should be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims. The scope of the invention is thusindicated by the appended claims and all changes which come within themeaning and range of equivalency of the claims are therefore intended tobe embraced.

What is claimed is:
 1. A method of processing a substrate, comprising:forming a trench in the substrate; depositing imprint material at leastinto the trench, thereby contacting at least one sidewall of the trenchwith the imprint material; embossing the imprint material in the trenchusing a stamp device, thereby at least partially displacing the imprintmaterial from the at least one sidewall of the trench; removing thestamp device from the trench; depositing filling material at least intothe trench after removal of the stamp device, thereby at least partiallycontacting the filling material with the at least one sidewall of thetrench; and removing, from the trench, the imprint material afterdepositing the filling material; wherein the filling material remains incontact with the sidewall of the trench after removal of the imprintmaterial.
 2. The method of claim 1, wherein the substrate comprises asemiconductor substrate.
 3. The method of claim 1, wherein the imprintmaterial comprises a hardenable material.
 4. The method of claim 3,further comprising hardening the imprint material after embossing andbefore removal of the stamp device.
 5. The method of claim 3, whereinthe hardenable material comprises a polymerizable material.
 6. Themethod of claim 4, wherein hardening the imprint material comprises atleast one of: exposing the imprint material to light; tempering thesubstrate; applying an electrical voltage to the imprint material. 7.The method of claim 1, further comprising depositing filling material atleast into the trench after removal of the stamp device.
 8. The methodof claim 7, wherein the filling material comprises metal.
 9. The methodof claim 7, wherein depositing the filling material comprises a platingprocess.
 10. The method of claim 1, wherein the stamp device comprisesan imprint pattern corresponding to a three-dimensional mask structureto be formed at least in the trench.
 11. The method of claim 1, whereinthe stamp device comprises a metal.
 12. The method of claim 1, whereinthe stamp device comprises a flexible material.
 13. The method of claim6, wherein the stamp device comprises a transparent material; andwherein hardening the imprint material comprises exposing the imprintmaterial to light.
 14. The method of claim 1, further comprising:forming at least one additional trench in the substrate; depositingimprint material into the at least one additional trench; embossing theimprint material in the at least one additional trench using the stampdevice; removing the stamp device from the at least one additionaltrench.
 15. The method of claim 14, wherein embossing the imprintmaterial in the at least one additional trench is carried out afterembossing the imprint material in the trench.
 16. The method of claim14, wherein embossing the imprint material in the at least oneadditional trench and embossing the imprint material in the trench arecarried out simultaneously.
 17. The method of claim 1, whereindepositing the imprint material at least into the trench furthercomprises depositing the imprint material over at least a part of thesubstrate surface; and wherein embossing the imprint material using thestamp device further comprises embossing the imprint material depositedover the substrate surface.
 18. The method of claim 1, wherein the stampdevice comprises an imprint stamp.
 19. The method of claim 1, whereinthe stamp device comprises a roll.
 20. The method of claim 1, whereinthe substrate comprises a printed circuit board.
 21. A method ofprocessing a substrate, comprising: forming a trench in the substrate;depositing imprint material over the substrate, thereby filling thetrench at least partially with the imprint material and at leastpartially contacting at least one sidewall of the trench with theimprint material; embossing the imprint material in the trench by meansof an imprint stamp having an imprint pattern that corresponds to aninverse of a mask structure, thereby forming the mask structure at leastin the trench and at least partially displacing the imprint materialfrom the at least one sidewall of the trench; hardening the embossedimprint material; removing the imprint stamp from the trench; depositingfilling material over the substrate after removal of the imprint stampdevice, thereby at least partially contacting the filling material withthe at least one sidewall of the trench; and removing, from the trench,the imprint material after depositing the filling material over thesubstrate; wherein the filling material remains in contact with thesidewall of the trench after removal of the imprint material.
 22. Themethod of claim 21, wherein hardening the embossed imprint materialcomprises at least one of: exposing the imprint material to light;tempering the substrate; applying an electrical voltage to the imprintmaterial.
 23. The method of claim 21, wherein the imprint materialcomprises imprint resist.
 24. The method of claim 21, wherein depositingthe filling material over the substrate after removal of the imprintstamp comprises filling at least parts of the trench that are free fromthe embossed imprint material with the filling material.
 25. The methodof claim 21, wherein the filling material comprises metal.